KR20070068413A - Aqueous Polyurethane Dispersions Prepared from Hydroxymethyl-Containing Polyester Polyols Derived from Fatty Acids - Google Patents

Abstract

A polymer dispersion is prepared by reacting a hydroxymethyl-containing polyester polyol derived from polyisocyanate and fatty acid to form a prepolymer, dispersing the prepolymer in an aqueous phase, and then curing the prepolymer to form solid particles. Prepolymers with isocyanates, hydroxy, or various other reactive functional groups can be prepared. Dispersions are useful in a variety of coatings, sealants, adhesives and elastomeric applications.

Description

Aqueous Polyurethane Dispersion Prepared from Hydroxymethyl-Containing Polyester Polyols Derived from Fatty Acids TECHNICAL FIELD

This application claims the benefit of US Provisional Application No. 60 / 622,217, filed October 25, 2004.

The present invention relates to dispersions of polyurethane and / or polyurea polymers in an aqueous continuous phase.

Aqueous polyurethane dispersions are used in a variety of film, coating, adhesive and sealant applications. Typically, such dispersions are prepared by forming an isocyanate-terminated prepolymer, dispersing the prepolymer in an aqueous phase, and then forming the polyurethane and / or urea polymer by chain-extension of the prepolymer. The prepolymer itself is prepared by reaction of excess polyisocyanate with polyol. Two types of polyols are generally used. The first type is polyether polyols, which are typically polymers of propylene oxide or propylene oxide / ethylene oxide mixtures. The second major type of polyol is a polyester polyol which can be derived from cyclic lactones such as caprolactone, or can be derived from low molecular weight diols and dicarboxylic acid anhydrides.

Such polyether and polyester polyols are almost always derived from oil, gas or coal sources. As these sources are not renewable, there is concern about the depletion of the natural sources from which they originate. In addition, geopolitical factors often result in unexpected costs of these sources. For this reason, there is a need to develop polyols derived from renewable sources. Various types of such polyols have been developed. However, these polyols are significantly different in structure, reactivity and other properties with commonly available polyether and polyester polyols, so that most applications find no drop-in substitutes for these materials. I couldn't. To date, polyols derived from renewable sources have found only limited applications.

In aqueous polyurethane dispersion applications, even polyether and polyester polyols have found some limitations on their use. Polyurethane coatings, films and sealants made from polyether polyol-based dispersions tend to degrade when exposed to light. These polyurethanes sometimes have worse properties than those made using polyester polyols. Poor stress crystallinity is a common example of this property. On the other hand, polyester polyol based polyurethanes tend to hydrolyze due to the reaction of ester groups with water molecules in the aqueous phase of the dispersion. This reduces the polymer molecular weight and the crosslink density, while at the same time lowers the physical properties of the polymer.

Thus, it would be desirable to provide a dispersion of polyurethane particles in an aqueous phase, in which a substantial portion of the raw materials used to make polyurethanes are derived from renewable sources. It would also be desirable for the resulting polyurethanes to have good stability against light and hydrolysis, and other good physical and other properties.

The present invention includes a polyurethane resin wherein the dispersed polyurethane particles are a reaction product of a polyisocyanate, at least one curing agent and at least one high equivalent material having isocyanate-reactive groups, wherein the high equivalent material is derived from fatty acids. Dispersion of polymer particles in a continuous aqueous phase comprising the above hydroxymethyl-containing polyester polyols.

  The present invention also relates to dispersing a urethane group- or urea group-containing prepolymer in an aqueous phase to form dispersion droplets containing the prepolymer, and curing the prepolymer to form solid polymer particles dispersed in the aqueous phase. A process for preparing a polyurethane particle dispersion in a continuous aqueous phase, wherein the prepolymer is a reaction product of a reactant comprising a polyisocyanate and an isocyanate-reactive material, wherein the isocyanate-reactive material is one or more high Equivalent hydroxymethyl-containing polyester polyols.

The high equivalent materials are suitably hydroxymethyl group-containing fatty acids having 12 to 26 carbon atoms or esters of such hydroxymethyl group-containing fatty acids, with an average of at least two hydroxy, primary amines and / or secondary The hydroxymethyl-containing polyester polyols comprise at least 10% by weight of at least one hydroxymethyl-containing polyester polyol prepared by reacting a polyol having a amine group or a polyamine initiator compound. It contains an average of at least 1.3 repeating units derived from hydroxymethyl group-containing fatty acids or esters thereof for each of the primary and secondary amine groups, and has an equivalent of at least 400 and up to 15,000.

Another aspect of the present invention includes a coating, sealant or adhesive composition prepared from a dispersion containing or prepared according to the present invention. In another aspect, the invention is a film, coating, curing sealant or curing adhesive prepared from a dispersion of the invention or a dispersion prepared according to the invention.

Much of the dispersed polyurethane particles are derived from renewable plant sources such as corn, soybeans and other oil-producing plants, or animal fats. Surprisingly, dispersions can be readily prepared by well known methods of preparation, and the polymers themselves are comparable to those made using conventional polyether and polyester polyols and in some cases have better properties. For example, in some cases the polymeric material exhibits improved hydrolysis resistance / stability compared to similar materials made using conventional aliphatic polyester polyols such as adipates and even caprolactone based polyester polyols. Such polymeric materials often exhibit less water absorption than similar materials made from conventional polyether polyols, which are particularly useful for applications such as waterproof membranes, for example. Low absorbency is also useful in many adhesive applications, and generally in any application where the final product is exposed to wet conditions or direct contact with water. Polymeric materials also sometimes exhibit good acid-etch resistance, which is an important parameter in determining weatherability. Coatings made using the present invention often exhibit good flexibility, particularly in applications requiring a balance of hardness and flexibility.

In the present invention, the term "polyurethane" is used as an abbreviation for the chain-extended isocyanate-terminated prepolymer. "Polyurethane" may contain urethane bonds, urea bonds, silanes, esters or other groups, or generally a combination of two or more thereof. The prepolymer itself may contain urethane or urea groups, or combinations thereof, even before chain extension.

Although not critical to the invention, the prepolymer is preferably water dispersible. By “water dispersible” is meant that the prepolymer is dispersed in water to form a dispersion without significantly separating the aqueous phase and the prepolymer phase into layers. Water dispersible prepolymers tend to provide at least two advantages: first, it is easy to produce stable dispersions of the prepolymer droplets during the dispersing step, and second, to form smaller droplets (which also tend to improve stability). To facilitate). However, with suitable choice of external surfactant (s) and / or co-stabilizers described in more detail below, or using a continuous process, these properties can also be achieved with prepolymers that are not water dispersible.

Water dispersibility is facilitated by introducing hydrophilic groups such as poly (ethylene oxide) chains, carboxylic acids, carboxylates, phosphates, sulfonates or ammonium groups into the prepolymer structure, as described in more detail below.

The prepolymer is preferably a liquid or a solid having a melting point of less than about 80 ° C., in particular less than 50 ° C. Most preferably, the prepolymer is liquid at 22 ° C.

If the polyurethane / vinyl polymer composite particles are to be prepared (as discussed in more detail below), the prepolymer is also suitably soluble in the ethylenically unsaturated monomer (s) used.

The prepolymer contains free reactive functional groups. Examples of these are, for example, isocyanate, hydroxy, amino, hydrolyzable silanes, ethylenically unsaturated, epoxide, carboxylic acid or carboxylic anhydride groups. The prepolymer suitably has a molecular weight of about 200,000 or less, in particular about 50,000 or less. Preferred prepolymers have a number average molecular weight of about 500, about 800, about 1,000 or about 1,200, to about 25,000, about 15,000, about 12,000, about 8,000 or about 6,000.

Preferred prepolymers contain free isocyanate groups. The isocyanate content of such prepolymers can be in a very wide range, such as from 0.5% to 35% by weight based on the total weight of the prepolymer. The optimum isocyanate content will vary depending on the application. In general, the polyurethanes produced are hard and harder when the isocyanate content is relatively high, such as 15 to 35% by weight, while the polyurethanes produced are soft and less hard when the content of isocyanates is low. Preferred isocyanate contents for many applications are from 0.5 to 12% by weight, more preferably from 1 to 10% by weight and in particular from 4 to 9% by weight.

Another preferred prepolymer contains hydroxy groups. Such prepolymers may have a hydroxy equivalent weight of about 150 to about 8,000. Rigid and harder polyurethanes are generally prepared using lower equivalents of prepolymer, such as those having a hydroxy equivalent weight of about 150 to about 500. The more elastic hydroxy-terminated prepolymer has a hydroxy equivalent weight of 500 to about 3,000.

The prepolymer has an average of at least 1.5, preferably at least 1.8 functional groups / molecules, up to 8 functional groups / molecules, preferably up to 6 functional groups / molecules, more preferably up to 4 functional groups / molecules , And in particular up to three functional groups / molecules.

The viscosity of the prepolymer is suitably up to 50,000 cps (50 Pa · s) at 25 ° C., preferably up to 20,000 cps (20 Pa · s), in particular up to 10,000 cps (10 Pa · s), and most preferably 1,000 cps (1.0 Pa · s) or less. This low viscosity facilitates the control of particle size and polydispersity index (particle size distribution). When using high viscosity prepolymers, it is generally desirable to dissolve the prepolymer in any suitable solvent to reduce its viscosity. Volatile solvents have the advantage of being removable from the product dispersion to reduce VOCs. The solvent may also perform some other useful function. For example, monomeric isocyanates can be used as the solvent, in which case the monomer isocyanates will polymerize into a dispersed polyurethane polymer. Another option is to use ethylenically unsaturated monomers or mixtures thereof as solvent. The ethylenically unsaturated monomers may be polymerized to form polyurethane / vinyl polymer composite particles. Such particles may have the form of interpenetrating networks or core shells.

The prepolymer is the reaction product of an organic polyisocyanate material and an isocyanate-reactive material having at least two isocyanate-reactive groups. To provide a prepolymer with free isocyanate groups, excess polyisocyanate is used. If an isocyanate-reactive substance is provided in excess, free hydroxy groups are provided.

Isocyanate-reactive materials include hydroxymethyl-containing polyester polyols derived from fatty acids. The term “derived from fatty acids” is used herein to refer to materials prepared using fatty acids or fatty acid esters as starting materials or intermediates. Hydroxymethyl-containing polyester polyols are characterized as having an average of at least one ester group per molecule and at least one hydroxymethyl (-CH ₂ OH) group per molecule. The hydroxymethyl-containing polyester polyols suitably have an average of at least two, preferably at least 2.5, more preferably at least 2.8 and up to about 12 or less hydroxy, primary and secondary amine groups per molecule in combination More preferably about 6 or less, even more preferably about 5 or less. The hydroxymethyl-containing polyester polyols are also suitably at least 400, such as at least about 600, at least about 650, at least about 700, or at least about 725 equivalents, up to about 15,000, such as up to about 6,000, up to about 3,500, about 1,700 or less, about 1,300 or less, or about 1,000 or less. Equivalent is the number average molecular weight of the molecule divided by the combined number of hydroxy, primary amine and secondary amine groups.

Hydroxymethyl-containing polyester polyols are typically esters of hydroxymethyl group-containing fatty acids having 12 to 26 carbon atoms, or such hydroxymethylated fatty acids, with an average of at least 1.0 hydroxy, primary amine and / or Or by reacting a polyol, hydroxyamine or polyamine initiator compound having a secondary amine group / molecule. The resulting hydroxymethyl-containing polyester polyols contain an average of at least 1.3 repeating units derived from hydroxymethyl group-containing fatty acids or esters thereof for each of the hydroxy, primary amine and secondary amine groups of the initiator compound and The proportion of starting materials and reaction conditions are selected such that the hydroxymethyl-containing polyester polyols have an equivalent of at least 400 and up to about 15,000.

Hydroxymethyl-containing polyester polyols are advantageously mixtures of compounds having an average structural formula of the general formula (I)

Wherein R is a residue of an initiator compound having z hydroxy and / or primary or secondary amine groups, z is at least 2, and each X is independently -O-, -NH- or -NR'- ( Wherein R 'is an inert substituted alkyl, aryl, cycloalkyl or aralkyl group), p is a number from 1 to z representing the average number of [XZ] groups per hydroxymethyl-containing polyester polyol molecule, and Z is one Straight or branched chain containing A groups, wherein the average number of A groups per molecule is at least 1.3 times z, and each A is independently selected from the group consisting of A1, A2, A3, A4 and A5, provided that at least Some A groups are A1, A2 or A3, wherein A1 is represented by formula II, A2 is represented by formula III, A3 is represented by formula IV, A4 is represented by formula V, A5 is represented by formula VI

Wherein B is a covalent bond with a carbonyl carbon atom of H or another A group, m is a number greater than 3, n is at least 0 and m + n is 8 to 22, in particular 11 to 19.

Wherein B is as above, v is a number greater than 3, r and s are each a number greater than or equal to 0, and v + r + s is 6-20, in particular 10-18.

Where B, v, each r and s are as defined above, t is a number greater than or equal to 0, and the sum of v, r, s and t is 5-18, in particular 10-18.

Where w is from 10 to 24.

Wherein R ′ is a linear or branched alkyl group substituted with one or more cyclic ether groups, and optionally with one or more hydroxy groups or other ether groups. Cyclic ether groups may be saturated or unsaturated and may contain other inert substituents. A "inert substituted" group is a group that does not react with isocyanate groups, in other words, does not participate in side reactions during the preparation of the hydroxymethyl group-containing polyester polyols. Examples of such inert substituents are aryl, cycloalkyl, silyl, halogen (particularly fluorine, chlorine or bromine), nitro, ethers, esters and the like. Hydroxy groups can be present in alkyl chains or cyclic ether groups, or both. The alkyl group may comprise a second terminal -C (O)-or -C (O) O- group capable of binding to another initiator molecule. A5 groups are generally lactols, lactones, saturated or unsaturated cyclic ethers or dimers, which are formed as impurities during the preparation of hydroxymethyl group-containing fatty acids or esters. The A5 group may contain 12 to 50 carbon atoms.

In formula (I), z is preferably 2 to 8, more preferably 2 to 6, even more preferably 2 to 5, and especially about 3 to 5. Each X is preferably -O-. The total average number of A groups per molecule of hydroxymethylated polyol is preferably at least 1.5 times the z value, for example about 1.5 to about 10 times, about 2 to about 10 times or about 2 to about 5 times the z value. .

A is preferably a mixture of A1, A1 and A2, a mixture of A1 and A4, a mixture of A1, A2 and A4, a mixture of A1, A2 and A3, or a mixture of A1, A2, A3 and A4, in each case Optionally contains large amounts of A5. The mixture of A1 and A2 preferably contains A1 and A2 groups in a molar ratio of 10:90 to 95: 5, in particular 60:40 to 90:10. The mixture of A1 and A4 preferably contains A1 and A4 groups in a molar ratio of 99.9: 0.1 to 70:30, in particular 99.9: 0.1 to 85:15. The mixture of A1, A2 and A4 preferably contains about 10 to 95 mol% A1 groups, 5 to 90 mol% A2 groups and up to about 30 mol% A4 groups. More preferred mixtures of A1, A2 and A4 contain 25 to 70 mol% A1 groups, 15 to 40 mol% A2 groups and up to 30 mol% A4 groups. The mixture of A1, A2 and A3 preferably contains 30 to 80 mol% A1, 10 to 60 mol% A2 and 0.1 to 10 mol% A3 groups. The mixture of A1, A2, A3 and A4 groups preferably contains 20 to 50 mol% A1, 1 to about 65 mol% A2, 0.1 to about 10 mol% A3, and up to 30 mol% A4 groups. . Particularly preferred polyester polyols of the present invention contain a mixture of 20-50% A1 groups, 20-50% A2 groups, 0.5-4% A3 groups, and 15-30% A4 groups. In all cases, the A5 groups advantageously comprise 0 to 7%, in particular 0 to 5% of all A groups.

Preferred mixtures of A groups typically have an average of about 0.8 to about 1.5 -CH ₂ OH and -CH ₂ OB groups / A groups, for example about 0.9 to about 1.3 -CH ₂ OH and / or -CH ₂ OB groups. Or a -CH ₂ OH and / or -CH ₂ OB group / A group from about 0.95 to about 1.2. Such a mixture of A groups tends to (1) the initiator functionality predominantly determine the functionality of the polyester polyol, and (2) to form less densely branched polyester polyols.

The hydroxymethyl-containing polyester polyols according to formula (I) can be prepared in a multistage process from vegetable or animal fats containing at least one carbon-carbon double bond in at least one chain of constituent fatty acids. Suitable fats include, for example, cinnamon oil, canola oil, citrus seed oil, cacao oil, corn oil, cottonseed oil, lard, flaxseed oil, oat oil, olive oil, palm oil, peanut oil, rapeseed oil, rice bran oil, safflower oil, sesame oil, soybean oil, Sunflower seed oil or uji.

Typically, vegetable or animal fats are first transesterified with lower alkanols, especially methanol or ethanol, to produce alkyl esters of constituent fatty acids. The resulting alkyl ester can optionally be hydrolyzed to the corresponding fatty acid, but this step is usually not necessary or desirable. Typically, alkyl esters (or fatty acids) are hydroformylated by reaction with carbon monoxide and hydrogen. This introduces a -CHO group onto the fatty acid chain at the carbon-carbon unsaturated site. Suitable hydroformylation methods are described, for example, in US Pat. Nos. 4,731,486 and 4,633,021 and WO 04/096744. Some fatty acid groups contain multiple carbon-carbon double bond sites. In such cases, the hydroformylation reaction may not introduce the -CHO group at all double bond sites. In the subsequent hydrogenation step, the remaining carbon-carbon bonds are hydrogenated to remove essentially all carbon-carbon unsaturations, converting the -CHO group to a hydroxymethyl (-CH ₂ OH) group. The resulting mixture of hydroxymethylated fatty acids is then reacted with the initiator compound to form a polyester polyol while removing water or lower alkanols.

The initiator contains one or more, preferably two or more hydroxy, primary amine or secondary amine groups and may be a polyol, alkanol amine or polyamine. Of particular interest is a polyol. Useful are polyether polyol initiators comprising polymers of ethylene oxide and / or propylene oxide having 2 to 8, in particular 2 to 4 hydroxy groups / molecules and a molecular weight of 150 to 3000, in particular 200 to 1,000.

The hydroxymethyl-containing fatty acids prepared in the above process tend to be a mixture of a substance having no hydroxymethyl group and a substance having 1, 2 or 3 hydroxymethyl groups. Since hydroformylation reactions often do not occur at all carbon-carbon double bonds unless stringent reaction conditions are used, the proportion of materials having two and three hydroxymethyl groups is typically two and three carbon-carbon doubles. Somewhat lower than the proportion of starting fatty acid (or alkyl ester) containing the bond. Non-hydroformylated carbon-carbon double bonds generally hydrogenate.

A process for preparing such hydroxymethyl-containing polyester polyols is described in WO 04/096744.

The hydroxymethyl-containing polyester polyols thus produced generally contain some unreacted initiator compound and may contain unreacted hydroxymethylated fatty acids (or esters). Initiator compounds often react only with monofunctional or difunctional fatty acids (or esters), and the resulting polyester polyols often contain free hydroxy groups or amino groups directly bonded to the residues of the initiator compound.

Hydroxymethyl-containing polyester polyols are alkoxylated as necessary to introduce the polyether chains onto one or more hydroxymethyl groups. Hydroxymethyl-containing polyester polyols can also be aminated via reactive amination processes.

The hydroxymethyl-containing polyester polyols can be blended with one or more other materials that react with isocyanate groups, including materials having one or more hydroxy, primary amine, secondary amine or epoxide groups. Such other isocyanate-reactive materials can be of various types. For example, other isocyanate-reactive materials having an equivalent of at least 400, in particular from about 400 to about 8,000, or from about 500 to about 3,000, or from about 600 to about 2,000 can be used. Examples of such high equivalent materials are polyether polyols, polyester polyols and aminated polyethers. They will typically have about 1 to about 8, in particular about 1.8 to about 3.5 functionalities (number of isocyanate-reactive groups / molecules). Polyethers of interest include, for example, homopolymers of propylene oxide, ethylene oxide or tetrahydrofuran, and random and / or block copolymers of propylene oxide and ethylene oxide. Polyesters of interest include polylactone and butanediol / adipate polyesters.

The hydroxymethyl-containing polyester polyols may be blended with chain extenders and / or crosslinkers as described in more detail below.

It is particularly preferable to include at least one substance that imparts hydrophilicity to the prepolymer. This property makes the prepolymer easier to disperse, thereby facilitating the formation of fine prepolymer droplets, thereby ultimately forming a more stable polymer dispersion. Among these types of materials are polymers of ethylene oxide, including copolymers of ethylene oxide with propylene oxide or other copolymerizable monomers. The polymer containing oxyethylene units may be a homopolymer of ethylene oxide, a random copolymer of ethylene oxide and another alkylene oxide, or a block copolymer of ethylene oxide and another alkylene oxide. Advantageously it contains on average one or more isocyanate-reactive groups / molecules. Examples of such isocyanate-reactive polymers include (A) random copolymers of propylene oxide and ethylene oxide, wherein the oxyethylene units comprise about 5 to 95%, in particular 10 to 75%, of the total amount of the copolymer; (B) poly (propylene oxide) polymers having terminal poly (ethylene oxide) blocks, which constitute 5 to 90%, in particular 5 to 60%, of the total polymer; (C) polyethers having at least one internal poly (ethylene oxide) block, which constitute 5 to 80%, in particular 5 to 50%, of the total amount of polyethers; And (D) homopolymers of ethylene oxide.

Another particularly preferred material used to prepare the prepolymer is a hydroxy-functional carboxylic acid or salt thereof and the counter ion is a monovalent metal or an ammonium group. The presence of carboxylate groups also tends to impart hydrophilicity to the prepolymer. This material preferably contains at least two hydroxy groups / molecules. Generally these types of materials obtained are dimethylolpropionic acid (DMPA) or salts thereof.

Other preferred materials used to prepare the prepolymers are polymers of polyester polyols with propylene oxide such as 1,4-butanediol / adipate polyester polyols.

The hydroxymethyl-containing polyester polyols will typically comprise at least 10%, at least 25%, at least 35%, or at least 50% of the total weight of the isocyanate-reactive material used to prepare the prepolymer. The hydroxymethyl-containing polyester polyols may comprise at least 75%, at least 85%, at least 90%, at least 95%, or even 100% of the total weight of the isocyanate-reactive material. For example, the hydroxymethyl-containing polyester polyol (s) may comprise 20 to 65%, 35 to 65%, 35 to 100%, or 50 to 80% of the total weight of the isocyanate-reactive material.

Collectively, the isocyanate-reactive material advantageously has at least 1.5, preferably at least 1.8, isocyanate-reactive groups per molecule. It preferably has on average 8 or less, more preferably 6 or less, even more preferably 4 or less, and especially 3 or less isocyanate-reactive groups per molecule. When used in combination with other isocyanate-reactive substances with more isocyanate-reactive groups such that the mixture has, on average, at least 1.5 isocyanate-reactive groups per molecule, the individual isocyanate-reactive substances may have as few as one isocyanate-reactive group per molecule. have.

Organic polyisocyanates that can be used to prepare the prepolymer include aliphatic, cycloaliphatic, arylaliphatic, aromatic isocyanates and mixtures thereof. Aromatic isocyanates, especially aromatic polyisocyanates, are preferred.

Examples of suitable aromatic isocyanates include 4,4'-, 2,4'- and 2,2'-isomers, blends thereof, and polymer and monomeric MDI blends, toluene-2,4- of diphenylmethane diisocyanate (MDI) And 2,6-diisocyanate (TDI), m- and p-phenylene diisocyanate, chlorophenylene-2,4-diisocyanate, diphenylene-4,4'-diisocyanate, 4,4'-diisocy Anato-3,3'-dimethyldiphenyl, 3-methyldiphenyl-methane-4,4'-diisocyanate, diphenyletherdiisocyanate, 2,4,6-triisocyanatotoluene and 2,4, 4'- triisocyanato diphenyl ether is mentioned.

Mixtures of isocyanates can be used, for example commercially available mixtures of toluene diisocyanate 2,4- and 2,6-isomers. Crude polyisocyanates such as crude toluene diisocyanate obtained by phosgenation of toluene diamine isomer mixtures or crude diphenylmethane diisocyanate obtained by phosgenation of crude methylene diphenylamine can also be used in the practice of the present invention. TDI / MDI blends can also be used.

Examples of aliphatic polyisocyanates include ethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,3- and / or 1,4-bis (isocyanatomethyl) cyclohexane (including cis and / or trans isomers), Isophorone diisocyanates, saturated homologs of the aromatic isocyanates described above (eg, H ₁₂ MDI), mixtures thereof, and the like.

The prepolymer is prepared by mixing the polyisocyanate with the isocyanate-reactive material (s) under conditions sufficient to effect the reaction of the isocyanate and isocyanate-reactive groups. The preparation of such prepolymers is well known and specific reaction conditions are not critical to the present invention as long as they form the prepolymers with the functional groups described above. Typically, (a) trimethylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N, N-dimethylbenzylamine, N, N-dimethylethanolamine, N, N, N ', N' Tertiary such as tetramethyl-1,4-butanediamine, N, N-dimethyl piperazine, 1,4-diazobicyclo-2,2,2-octane, bis (dimethylaminoethyl) ether and triethylenediamine Amines; (b) tertiary phosphines such as trialkylphosphines and dialkylbenzylphosphines; (c) acetylacetone, benzoyl acetone, trifluoroacetyl acetone, ethyl acetoacetate and the like, Be, Mg, Zn, Cd, Pd, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co and Chelates of various metals obtainable from metals such as Ni; (d) acidic metal salts of strong acids such as iron (III) chloride, tin chloride (IV), tin chloride (II), antimony (III) chloride, bismuth nitrate and bismuth chloride; (e) strong bases such as alkali and alkaline earth metal hydroxides, alkoxides and phenoxides; (f) alcoholates and phenolates of various metals, such as Ti (OR) ₄ , Sn (0R) ₄ and A1 (OR) ₃ , where R is alkyl or aryl, alcoholates and carboxylic acids, β- Reaction products of diketones and 2- (N, N-dialkylaminoalcohols); (g) salts of organic acids with various metals such as alkali metals, alkaline earth metals, Al, Sn, Pb, Mn, Co, Ni and Cu, eg Metal desiccants such as, for example, sodium acetate, tin (II) octoate, tin (II) oleate, lead octoate, and manganese and cobalt naphthenate; (h) tetravalent tin, trivalent and pentavalent As, Sb And the reaction is carried out in the presence of an organometallic derivative of Bi and a metal carbonyl of iron and cobalt, and (i) a catalyst such as a mixture of two or more of the above. Prepolymers are optionally prepared without solvents or in solvents.

The reaction product of polyisocyanate and isocyanate-reactive material will in most cases contain isocyanate groups or hydroxy groups. Typically, other kinds of functionality must be introduced separately. This sensuality can be introduced in several ways. One method is to chemically modify the functional groups present to convert them into another preferred functional group. One example of this is the conversion of terminal isocyanate groups to urethane or urea groups by reaction with primary alcohols or water, and hydrolysis of the urethane or urea groups to form terminal primary amino groups. Another example is the oxidation of terminal hydroxy groups to form carboxylic acid groups.

Another method is to react the existing functional groups with both reactive materials that contain both desired new functional groups and second functional groups that will react with existing functional groups on the prepolymer to form covalent bonds.

Both reactive materials useful for imparting specific functionality to isocyanate-terminated urethanes include hydroxy- or amino-functional ethylenically unsaturated compounds such as hydroxyalkyl acrylates and methacrylates, aminoalkyl acrylates and methacrylates. , Hydroxy-functional carboxylic acids and carboxylic anhydrides, hydroxy-containing epoxide compounds such as bisphenol-A / glycidyl ether-type epoxides, hydroxy- or amino-functional alkoxy silanes, and the like. . The diamine used in excess can be used to introduce terminal amino groups into the isocyanate-terminated prepolymer.

Both reactive materials useful for imparting specific functionality to hydroxy-terminated urethanes include ethylenically unsaturated isocyanates such as isocyanatoethyl methacrylate, ethylenically unsaturated carboxylic acids, acid halides or acid anhydrides, epoxy-functional As well as ethylenically unsaturated alkoxy silanes such as isocyanate, carboxylic acid, acid halide or acid anhydride, vinyl trimethoxysilane, as well as many others.

Processes for the preparation of epoxy-functional adducts from hydroxy-functional materials are described, for example, in US Pat. No. 4,599,401, and European Patent 139,042, European Patent 143,120 and European Patent 142,121. Such a method can be applied and used in the present invention. Specific methods for introducing terminal alkoxysilane groups are described in US Pat. No. 6,762,270.

In addition, the prepolymer may contain two or more different types of functional groups. Such prepolymers may be involved in various types of curing reactions. This is especially the case when the prepolymer contains ethylenic unsaturations. In such cases, the prepolymer advantageously contains isocyanate and / or hydroxy groups in addition to ethylenic unsaturation. Prepolymers of that type can be cured to form dispersed polyurethane particles having ethylenic unsaturation. Polyurethane particles can be secondary cured or crosslinked by exposure to a free radical source or UV radiation.

To prepare the dispersion, the prepolymer is dispersed into the aqueous phase in a batch or continuous process. If the prepolymer is a solid at room temperature, it can be heated above its melting point to mix with the prepolymer.

The prepolymer is dispersed in the aqueous phase under conditions that form the droplets dispersed in the aqueous phase, with the prepolymer having an average diameter of 2,000 nm or less. Preferably, the droplets thus formed have an average diameter of 50 nm, more preferably 70 nm, to 1,000 nm, more preferably 800 nm, even more preferably 500 nm, and especially 250 nm. The weight of the dispersed phase (“solid” after the post curing reaction) can vary widely from slightly over 0% by weight of the dispersion to at least 60% by weight. The solids preferably constitute 10%, more preferably 20%, even more preferably 30%, 60%, more preferably 50% based on the weight of the dispersion.

In order to make the required droplet size, high shear mixing techniques such as homogenization or high pressure impingement mixing are useful. Suitable high shear impingement mixing devices are the MICROFLUIDIZER® emulsifiers available from Microfluidics Corporation. Such mixing devices are described in US Pat. No. 4,533,254. Ultrasonic mixing is also suitable. It is also possible to use electric photochromators and sonicators that convert electrical energy into high frequency mechanical energy. In addition, mechanical dispersing devices, such as IKA (IKA) or Omni (OMNI) type mixers, can be used to disperse the prepolymer / monomer mixture in the aqueous phase. Dispersion of the prepolymer into the aqueous phase, and subsequent process steps to produce the dispersed polymer particles, can be carried out continuously or batchwise.

The aqueous phase includes water. The aqueous phase may also contain external surfactants that stabilize the particles. By "external" is meant that the surfactant does not comprise a prepolymer or form a prepolymer part. However, if the prepolymer contains a hydrophilic group (eg poly (oxyethylene group)), it can provide sufficient compatibility with the aqueous phase to form stable droplets. The external surfactant will contain relatively hydrophilic as well as relatively hydrophobic groups and are more soluble in the aqueous phase than in the dispersed prepolymer droplets. Hydrophobic groups are adsorbed into the droplets while hydrophilic groups expand into the aqueous phase to cause stabilization. The surfactant will preferably be adsorbed onto the dispersed droplet phase to reduce the interfacial tension between the droplet and the aqueous phase to 5 dynes / cm or less.

Among the useful surfactants are a wide range of anionic, cationic and nonionic surfactants. Generally anionic and nonionic surfactants are preferred. Anionic and cationic surfactants may generally be characterized in that they contain one or more ionic (anionic or cationic) groups and hydrophobic groups. Suitable anionic groups include carboxylate groups and sulfonate groups. Suitable cationic groups include ammonium and phosphonium groups. Hydrophobic groups are preferably aromatic groups having at least 6 carbon atoms, aliphatic groups having at least 6, preferably 8 to 30 carbon atoms, or combinations of aromatic and aliphatic groups containing a total of 6 to 30 carbon atoms There is this. Preferred anionic and cationic surfactants contain one or more acyclic alkyl or alkenyl groups having six or more carbon atoms. In addition, the anionic and cationic surfactants may contain other moieties such as oxyalkylene groups, including oxyethylene and / or oxypropylene groups. Examples of suitable anionic and cationic surfactants include sodium lauryl sulfate, linear dodecyl benzyl sulfonate, triethanolaminelauryl sulfate, sodium dodecyl diphenyl oxide disulfonate, sodium n-decyl diphenyl oxide disulfonate, Sodium hexyl diphenyl oxide sulfonate, dodecyl benzene sulfonic acid, sodium or ammonium stearate, sodium abietic acid and the like. Examples of commercially available surfactants of this type include Stephan Chemical's Polystep ™ A-15 and Bisfot ™ S-100, Deforest's Desulf ™ TLS. -40, Dowfax ™ 2A1, 3B2 and C6L from The Dow Chemical Company, Emkapol ™ PO-18 from Emkay, Dresinate from Hercules ) TX, and Dow Chemical's Triton ™ X-100, X-405 and X-165, and the like.

Suitable nonionic surfactants are, for example, polymers of ethylene oxide and / or propylene oxide, in particular polymers of ethylene oxide, and contain various organosilicon surfactants as well as the hydrophobic groups described in the paragraphs above. Examples of suitable commercially available surfactants include Pluronics ™ L43 and L44 surfactants, Tetronic ™ 701 and 704 surfactants, all available from BASF, Tween ™ 20 interface from ICI. Active agents, and Igepal ™ CO-850 and CO-630 surfactants available from Rhone-Poulenc.

Most preferred surfactants are alkyl sulfates and alkyl sulfonate-type anionic surfactants, and mixtures of one or both thereof with nonionic surfactants.

The surfactant is preferably added to the aqueous phase before dispersing the prepolymer.

The dispersed prepolymer is subjected to conditions (depending on the curing mechanism) to cure to form a high molecular weight polymer with urethane and possibly urea or other groups. Curing refers to any type of reaction in which the prepolymer reacts by itself or with a curing agent to form solid polymer particles dispersed in an aqueous phase. Isocyanates on the prepolymer will react with water in the aqueous phase to form urea bonds and liberate carbon dioxide. Hydrolyzable silane groups will also react with water in the aqueous phase. Some degree of this reaction will tend to occur when the prepolymer is dispersed. Conditions such as, for example, heating the dispersed prepolymer to moderately elevated temperatures (ie, 30 ° C. to 100 ° C.) may be selected to facilitate the water / prepolymer reaction.

Alternatively, or in addition to curing with water, the prepolymer may be chain extended by contacting the dispersed prepolymer droplets with the added curing agent and applying the resulting mixture under conditions such that the curing agent reacts with the prepolymer. Curing agents are materials other than water, having two or more groups / molecules that react with functional groups on the prepolymer. Curing will in most cases have a weight of at most 400 per reactive group, preferably at most 150, in particular at most 80, and react with functional groups on the prepolymer molecules to form covalent linkages between them. Suitable curing agents for use with isocyanate-functional prepolymers include polyols, alkanolamines, various hydrazines, aminoalcohols and polyamines. Hydrazines and polyamines are preferred because of their generally higher reactivity with isocyanate groups. Specific examples of useful chain extenders include ethanolamine, isopropanol amine, diethanol amine, diisopropanol amine, ethylene diamine, diethylene triamine, triethylenetetraamine, propylene diamine, butylene diamine, cyclohexylenediamine, piperazine, 2-methyl piperazine, phenylenediamine, toluene diamine, tris (2-aminoethyl) amine, 4,4'-methylene-bis (2-chloroaniline), 3,3'-dichloro-4,4'-di Phenyldiamine, 4,4'-diphenyldiamine, 2,6-diaminopyridine, 4,4'-diamine diphenylmethane, isophorone diamine, diethyltoluene diamine, aminoethylethanolamine, diethylene triamine diethanol Adducts of amines, monoethanol amines and the like. Amines are preferred because amines react rapidly with polyisocyanates and isocyanate groups generally react with amines rather than with water.

Suitable curing agents for use with hydroxy-terminated prepolymers are the di- and polyisocyanate compounds described above. Emulsified water-containing polyisocyanates are particularly useful. Isocyanate-functional chain extenders and crosslinkers may comprise biuret, carbodiimide, urea, allophonate and / or isocyanurate linkages. Other curing agents that can be used with the hydroxy-terminated prepolymers include carboxylic acid anhydrides, polycarboxylic acids, polyacid halides, and the like.

Curing agents for use with epoxide-functional prepolymers include diamines and polyamine compounds.

Photoinitiators can be used to accelerate the curing of prepolymers containing ethylenic unsaturations, especially with acrylate and methacrylate groups.

If the curing agent is water soluble, it is most preferred to disperse the prepolymer therein and then add it to the aqueous phase. If a water insoluble curing agent is used, it is preferably mixed with the prepolymer before preparing the dispersion. In this case, a condition such as reduced temperature is preferably selected to prevent premature curing.

The dispersed prepolymer is then applied under conditions sufficient to cure the prepolymer. Such conditions generally include elevated temperatures such as 35 ° C. to 150 ° C., more preferably 70 ° C. to 130 ° C., but primary amine curing agents will often react sufficiently quickly with isocyanate groups even at room temperature (22 ° C.). Typically, the dispersion is mixed during the chain extension process to prevent agglomeration of the prepolymer droplets, facilitating mass transfer as well as heat transfer when the curing agent is added during polymerization.

Catalysts for the curing reaction can be used as necessary, but are not usually necessary, especially when the curing reaction is an amine-isocyanate reaction. Suitable catalysts for the reaction of the curing agent and isocyanate include, among others, well-known urethane catalysts such as tertiary amines, organo-tin, -mercury, -iron, -lead, -bismuth and -zinc compounds. Various transesterification catalysts can be used to cure the carboxylic acid, carboxylic anhydride or carboxylic acid halide curing agent and hydroxy-terminated prepolymer. Similarly, well known epoxy resin curing catalysts can be used when the prepolymer is an epoxide end.

Upon completion of the curing reaction, the dispersion droplets form solid polymer particles, which remain dispersed in the aqueous phase. Particle sizes are generally within the ranges described above in relation to the size of the dispersed prepolymer droplets, but are prepared while increasing or decreasing the average particle size, or in some cases forming various particle size distributions containing small amounts of very fine particles. Particle re-nucleation and / or aggregation can sometimes occur during the process.

The dispersion may also contain other components, such as solvents, but preferably these components, in particular volatile organic solvents, are excluded. The dispersions of the present invention may also be blended with other aqueous dispersions, including aqueous dispersions of epoxides, vinyl esters, polyolefins, other polyurethanes, acrylates and styrene-butadiene resins.

Another optional significant component is at least one ethylenically unsaturated monomer. These monomers can be blended with the prepolymer, and the resulting blend is dispersed together in the aqueous phase. The at least one ethylenically unsaturated monomer is liquid or solid at room temperature, most preferably liquid at room temperature. Preferably, the monomers are solvents for the prepolymer at relative proportions which are mixed together to form a dispersion. Preferably, the monomer (s) are substantially insoluble in water, ie less than 10 g, preferably less than 5 g, more preferably less than 2 g and in particular less than 1 g per 100 g of water at 25 ° C. Dissolves. In particular, if the water-soluble monomer forms a substantially water-insoluble oligomer (containing 10 or less repeating units), a higher water-soluble monomer can be used. However, the use of higher water solubility monomers is less preferred. When using relatively soluble monomers in water, it is sometimes necessary to maintain monomers dispersed in the prepolymer droplets using more hydrophilic prepolymers and / or using additional stability additives (e.g. co-stabilizers discussed below). Required.

Suitable monomers include aliphatic conjugated dienes such as butadiene and isoprene; Styrene, α-methyl styrene, ar-methyl styrene, ar- (t-butyl) styrene, ar-chlorostyrene, ar-cyanostyrene, ar-bromostyrene, dibromostyrene, tribromostyrene, 2, Monovinylidene aromatic monomers such as 5-dichlorostyrene, bromostyrene, fluorostyrene and trifluoromethylstyrene; Α, β-ethylenically unsaturated carboxylic acids and esters thereof, including itaconic acid, acrylic acid, methacrylic acid, and methyl methacrylate, ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethylmetha Acrylic and methacrylic esters such as acrylate, n-butyl acrylate, t-butyl acrylate, n-butyl methacrylate, t-butyl methacrylate, n-hexyl acrylate, maleic anhydride and the like; Α, β-ethylenically unsaturated nitriles and amides such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N, N-dimethylacrylamide, N- (dimethylaminomethyl) acrylamide and the like; Vinyl esters such as vinyl acetate; Vinyl ethers; Vinyl ketones; Vinyl and vinylidene halides such as vinylidene chloride and vinyl chloride; Maleimide, N-arylmaleimide, and N-alkylmaleimides such as maleimide and N-ethyl maleimide, 1-vinyl-2-pyrrolidinone and vinyl pyridine and the like. Mixtures of two or more of the aforementioned monomers are also suitable for preparing the copolymers. Of these, monovinyl aromatic and acrylic acid esters or methacrylic acid esters are preferred.

Monomers containing more than one site of polymerizable carbon-carbon unsaturation can be used as needed to form crosslinked polymers. Such monomers will typically comprise up to about 10 mol%, preferably about 0.25 to 5 mol%, of the total monomers. Except in the case of using conjugated diene monomers, it is most preferred not to use crosslinkable monomers. In addition, ethylenically unsaturated monomers containing other functional groups that may react form covalent bonds to the prepolymer. Suitable monomers of this type will include single site polymerizable carbon-carbon unsaturations and isocyanate-reactive groups such as hydroxy groups, epoxides or primary or secondary amino groups. Among the monomers of this type are 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxybutyl methacrylate, allyl alcohol, glycidyl methacrylate, diaminoethyl methacrylate, and the like. have.

If additional ethylenically unsaturated monomers are used, the weight ratio of prepolymer to monomer is 10:90, preferably 30:70, more preferably 40:60, to 90:10, preferably 80:20, most Preferably in the range of 75:25.

Typically, monomers (eg, isoprene and butadiene) that are gaseous at low boiling point or room temperature are added to the pre-formed dispersion of prepolymer / monomer mixture prior to the chain extension and polymerization steps. In order to use such monomers, a pressure vessel is conveniently filled with a dispersion of the prepolymer / monomer mixture in the aqueous phase and the vessel is pressurized with a gaseous monomer. The contents of the pressure vessel are then maintained with optional stirring until the gaseous monomer is dissolved in the dispersion in the desired amount. Since the gaseous monomers are typically hydrophobic, they will migrate through the aqueous phase to the prepolymer / monomer particles. In this way, the particle size is set before the polymerization takes place. In this case, the subsequent degree of polymerization is also carried out under pressure.

When ethylenically unsaturated monomers are present, the vinyl polymer is formed by conveniently providing free radical initiators to promote polymerization of the monomers. Preferably the initiator is predominantly distributed in the organic (prepolymer / monomer) phase, ie is not substantially soluble in the aqueous phase. Use of this type of initiator tends to minimize polymerization in the aqueous phase. However, it is believed that water soluble initiators can be used, and in most cases aqueous phase polymerization will produce oligomeric species that are partitioned into the organic phase where further polymerization proceeds. Useful initiators include free radical initiators such as peroxy compounds and azo compounds. Redox systems including reducing and oxidizing agents are also useful. Useful initiators include organic peroxides such as di-t-butyl peroxide, t-butylhydroperoxide, lauryl peroxide, dichlorobenzoyl peroxide, cumene hydroperoxide, and the like; Peroxycarbonates such as hydrogen peroxide, diisopropyl peroxydicarbonate, dicyclohexyl peroxy dicarbonate, etc., sulfonyl peroxides such as acetyl cyclohexyl sulfonyl peracetate, sulfonylhydrozide, 2,2 ' Such as azobis (2,4-dimethylpentanenitrile) and 2,2'-azobis-2-methylpropanenitrile (AIBN), 2,2-azobis (isobutyronitrile) t-butylhydroperoxide Azo compounds, inorganic peroxides such as ammonium peroxydisulfate, potassium peroxy disulfate, sodium metabisulfite / iron (II) ammonium sulfate, and the like. Of these, oil-soluble (ie, more soluble in droplets than aqueous phases) are most preferred. Also suitable are controlled living free radical polymerizations using a metal containing initiator, 2,2,6,6-tetramethylene piperadin-1-oxy (TEMPO). Such initiators can often be emulsified into a prepolymer / monomer mixture even if they are water soluble. This last type of polymerization gives particularly good control of the polymer molecular weight.

The amount of initiator is selected to provide a controlled reaction that proceeds at an economically useful rate. The exact amount will vary somewhat depending on the particular initiator, but generally from 0.05 to 5 weight percent is sufficient, based on the monomers. The initiator is preferably blended into the prepolymer / monomer mixture before the initiator is dispersed into the aqueous phase. In general, premature polymerization can be controlled by keeping it below the temperature at which the initiator produces a significant amount of free radicals.

In order to provide further particle stability, co-stabilizers can be used, especially when ethylenically unsaturated monomers are present. As used herein, co-stabilizers are materials other than prepolymers or ethylenically unsaturated monomers having a molecular weight of less than 300, preferably less than 200, and are soluble in water at 25 ° C. to about 10 ⁻⁵ g / l or less. Co-stabilizers are believed to promote the absorption of surfactants at the water / droplet interface to improve the stability of the dispersion. Among the suitable co-stabilizers are alkanes and alkanols having about 6 to 30 carbon atoms each. Preferred alkanes co-stabilizers include straight chain alkanes having 8 to 18, in particular about 10 to about 16, carbon atoms. Hexadecane is particularly preferred. Among the preferred alkanol stabilizers are straight chain alcohols having 8 to 22, in particular 12 to 20 carbon atoms.

The amount of external surfactant and co-stabilizer used varies somewhat depending on the particular system, but in general 0.1 to 5 parts by weight of surfactant is used per 100 parts by weight of the dispersion. If used, co-stabilizers generally comprise 0.1 to 3% of the total weight of the dispersion. If used, co-stabilizers may be added to the aqueous phase or prepolymer prior to adding the ethylenically unsaturated monomer.

It is generally preferred to simultaneously cure the prepolymer by polymerization of ethylenically unsaturated monomer (s), although in some cases this may be carried out sequentially. Both the curing agent and the free radical initiator are added to the dispersed prepolymer and the mixture is applied under conditions where both reactions will occur, thereby achieving co-polymerization and curing. In many cases, at least some of the resulting polymer particles are hybrid particles containing both polyurethane and vinyl polymers. The polymer may take the form of an interpenetrating polymer network, or exhibit a core-shell form. Techniques that favor the formation of core-shell particles are described, for example, in WO 02/055576 A2.

The resulting dispersions are useful in a variety of applications. This is useful for making a variety of films and coatings. To this end, the dispersion can be blended with various types of useful additives including, for example, pigments, dyes, fillers, desiccants, rheology and viscosity modifiers, dispersants, surfactants, preservatives, antibacterial agents, pesticides, fertilizers and the like. Formulated dispersions may be applied to any number of types of substrates.

Films can be prepared by agglomeration processes, or by simple casting and drying, using techniques well known in the art. Similarly, coatings are readily prepared by forming a dispersion layer on a substrate and drying and / or agglomerating polymer particles to form a continuous coating.

Dispersions are also useful for making cast articles, particularly thin articles such as gloves, condoms, including medical or surgical gloves. If desired, the dispersion may be combined with the various types of additives described above. The casting process typically involves applying the blended dispersion to a suitable shape and evaporating the aqueous phase to coalesce individual polymer particles to form a film over the shape. Drying can be carried out at ambient or elevated temperature. In order to increase the thickness, the casting process can be repeated as necessary.

The following examples are provided to illustrate the invention but are not intended to limit its scope. All parts and ratios are by weight unless otherwise indicated.

Example  1-5

A series of isocyanate-terminated prepolymers is prepared from the following components.

Polyether polyol A is an ethylene oxide-capped poly (propylene oxide) available as Doan Chemical's Boranol ™ 9287 polyol. It has a hydroxy equivalent of about 2,000. Polyether polyol B is an ethylene oxide-capped poly (propylene oxide) available from Dow Chemical's Boranol ™ 4701 polyol. It has a hydroxy equivalent of about 1,600. Polyester polyol A is a polycaprolactone diol having a number average molecular weight of about 850. It is marketed as Dow ™ 0210 polyol from Dow Chemical. HMPP A is a hydroxymethyl-containing polyester polyol having a hydroxy equivalent weight of about 1,000. This is the reaction product of methyl (9,10) -hydroxymethyl stearate and difunctional initiator. It has a functionality of about 2.0. HMPP B is a hydroxymethyl-containing polyester polyol having a hydroxy equivalent weight of about 1,600 and a hydroxy functionality of about 3. HMPP C is a hydroxymethyl-containing polyester polyol having an equivalent weight of about 420 and a functionality of about 2.0. This is the reaction product of methyl (9,10) -hydroxymethyl stearate and cyclohexane dimethylol. Poly (EO) A is a poly (ethylene oxide) diol having a molecular weight of 1,000. Poly (EO) B is a poly (ethylene oxide) monool having a molecular weight of 950. DMPA is dimethylolpropionic acid. Aromatic isocyanates A are mixtures containing 4,4'-diphenylmethane diisocyanate and small amounts of 2,4'-diphenylmethane diisocyanate as main components. Aliphatic isocyanate A is isophorone diisocyanate.

All prepolymers except Example 5 were prepared by charging polyols, poly (EO) and isocyanates into a stirred reactor. The reactor was purged with dry nitrogen and kept at 60 ° C. for 10-15 minutes. If necessary, sufficient benzoyl chloride was added to neutralize the basicity of the polyol. The reactor was then heated at 70 ° C. to 90 ° C. until a desirable conversion level was achieved (about 2 to 4 hours). The prepolymer was characterized by its NCO content percentage according to ASTM method D5155-96. The viscosity of the resulting prepolymer was then measured using a Brookfield LVF viscometer at 40 ° C. according to ASTM D 4878-88.

The prepolymer of Example 5 was used in the same manner, except that N-methyl pyrrolidone (NMP) was used as the solvent to facilitate the dissolution of DMPA into the other components and to reduce the viscosity of the resulting prepolymer. Prepared. In addition, the prepolymer was neutralized with triethyl amine during the chain-extension step to convert about 90% of the carboxylic acid groups of dimethylolpropionic acid to carboxylate groups.

Dispersions were prepared from each of these prepolymers by feeding the prepolymer continuously with a high shear mixer at a constant rate. The desired surfactants are combined at a constant rate by cooling (10 ° C. to 15 ° C.) deionized water stream (initial aqueous phase) and fed to a mixer to emulsify the prepolymers containing about 75 to 85% by weight of prepolymers. A first stage emulsion was formed. The high concentration dispersion present in the Ica mixer first stage emulsion was continuously passed through a second mixer to dilute it with an aqueous chain extender solution. The product was collected in a large vessel to release CO ₂ gas (which arises from the reaction of water with excess isocyanate groups).

The viscosity of each dispersion was measured at room temperature using a Brookfield viscometer. Solids content was about 54 to 58 weight percent in each case, as measured by an IR-200 Moisture Analyzer (Denver Instrument Company). After measuring the solids from which the volatile aqueous phase was removed using this instrument, the amount of remaining nonvolatile dispersed polymer phase was determined by gravimetry. The particle size of the dispersion ranged from 0.08 to 1.0 micrometers as measured by the dynamic light scattering technique using a Coulter LS 230 device. Shear stability of the dispersion was measured using a Hamilton beach mixer and an AR2000 flow meter supplied by TA Instruments.

Coatings were prepared from each of the dispersions by applying the dispersion onto a polished and dry cold rolled iron plate using a # 60 wire wound rod to achieve a target dry film thickness of 1.5 to 2.0 mils. The wet coating film was dried at room temperature for 30 minutes and then forced to dry at 80 ° C. for 120 minutes in an oven.

Example  6 and Comparative Sample D

Hydroxymethyl-containing polyester polyols, 330.4 g of methyl (9,10) -hydroxymethylstearate, 72.4 g of about a 1: 1 mixture of 1,3 and 1,4-cyclohexanedimethanol, and dibutyltin 0.411 g of oxide catalyst was prepared by filling into a 500 milliliter 5-neck round bottom glass flask equipped with a mechanical stirrer, condenser, addition funnel, nitrogen inlet, and sensors for monitor / control reaction temperature. The mixture was heated to 150 ° C. using an external hot oil bath with stirring and kept at that temperature for 1 hour. Thereafter, the temperature was raised in increments of 10 ° C. every 45 minutes until a final reaction temperature of 200 ° C. was obtained. A total of 30 g of methanol (90% theoretical yield) was collected and the resulting hydroxymethyl-containing polyester polyols were collected. It has a hydroxy equivalent weight of about 400.

78.15 g of hydroxymethyl-containing polyol, 8.21 g of dimethylolpropionic acid, 49.14 g of NMP and 0.0882 g of dibutyltin dilaurate catalyst were added to a mechanical stirrer, condenser, addition funnel, nitrogen inlet, monitor / control reaction temperature. -Filled into a 250 milliliter 5-neck round bottom glass flask equipped with a Therm-O-Watch sensor. The mixture was heated to 80 ° C. using an external hot oil bath with stirring. Nitrogen was sparged through the solution for 2 hours until the concentration of water was measured below 200 ppm. The reactor contents were then cooled to 75 ° C. 58.82 g of isophorone diisocyanate was slowly added to the reaction mixture at a rate which kept the reaction temperature at about 75 ° C. After all isocyanate was added, the reaction mixture was raised to about 83 ° C. and maintained at that temperature for 3 hours. 4.67 g of triethylamine was added and the temperature was maintained at about 83 ° C. for an additional 20 minutes. The reactor contents were then cooled to 60 ° C. and under high speed stirring a total of 166.7 g of the reaction mixture was added to an 8 oz. Glass jar containing 112.3 g of deionized water. 5.07 g of ethylene diamine in 55 g of deionized water was then added to the aqueous dispersion and high speed stirring was maintained for an additional 20 minutes to produce the dispersion of Example 6.

67.47 g of polycaprolactone diol (Ton® 210 of Dow Chemical), 6.75 g of dimethylolpropionic acid, 41.45 g of NMP, 45.17 g of isophorone diisocyanate and 0.0767 g of dibutyltin dilaurate are used to form a prepolymer; Neutralize the carboxylate group supplied by DMPA with 3.78 g of triethylamine; Comparative dispersion sample D was prepared in a similar manner by chain extending the prepolymer with 4.10 g of ethylene diamine.

The dispersions of Example 6 and Comparative Sample D were put down on the films described for Examples 1-5, respectively. The oven-cured coating was held for 24 hours before measuring its physical properties. Film thickness was measured according to ASTM D 1186. Glossiness was measured using a BYK Labertron Gloss Unit according to ASTM D 526. Impact resistance was measured using a Gardner Impact Tester and ASTM D 2794 below. Abrasion resistance was evaluated using a CS-17 wheel, 1, OO g weight and 500 cycles using a Taber grinder. Pencil hardness was measured according to ASTM D 3363. Acid etch resistance was measured by placing a 10% sulfuric acid solution droplet on the coating for 60 hours and observing visual effects on the film. Whitening of the coating surface indicates proper etching and bubbled coating surfaces show severe etching. Water resistance was evaluated in a similar manner using deionized water. The solvent resistance of the coating was recorded as the number of methyl ethyl ketone (MEK) friction required to cut through the coating to the substrate. The results are shown in the table below.

The coating made using the dispersion of Example 6 has the same good toughness (balance between hardness and flexibility), good appearance (high gloss) and good wear resistance as the coating made from Comparative Sample D. The water resistance and solvent resistance of the coatings prepared from the dispersion of Example 6 were better compared to Comparative Sample D.

Claims (23)

At least one hydroxy from which the dispersed particles comprise a polyisocyanate, at least one curing agent, and a polyurethane resin, the reaction product of at least one high equivalent material having an isocyanate-reactive group, wherein the high equivalent material is derived from a fatty acid. A dispersion of polymer particles in a continuous aqueous phase, comprising a methyl-containing polyester polyol. The hydroxymethyl-containing polyester polyols of claim 1, wherein the hydroxymethyl-containing polyester polyols contain from 12 to 26 carbon atoms containing hydroxymethyl groups or esters of such hydroxymethylated fatty acids, with an average of at least 2.0 hydroxy, primary amines And / or a dispersion that is a reaction product of a polyol, hydroxyamine or polyamine initiator compound having secondary amine groups / molecules. The dispersion according to claim 1 or 2, wherein the hydroxymethyl-containing polyester polyol has an average structural formula of the following formula (I). <Formula I>

Wherein R is a residue of an initiator compound having z hydroxy and / or primary or secondary amine groups, z is at least 2, and each X is independently -O-, -NH- or -NR'- ( Wherein R 'is an inert substituted alkyl, aryl, cycloalkyl or aralkyl group), p is a number from 1 to z representing the average number of [XZ] groups per hydroxymethyl-containing polyester polyol molecule, and Z is Straight or branched chains containing one or more A groups, wherein the average number of A groups per molecule is at least 1.3 times z, and each A is independently selected from the group consisting of A1, A2, A3, A4 and A5, At least some A groups are A1, A2 or A3, wherein A1 is represented by formula II, A2 is represented by formula III, A3 is represented by formula IV, A4 is represented by formula V, and A5 is represented by formula VI below. <Formula II>

Wherein B is a covalent bond with a carbonyl carbon atom of H or another A group, m is a number greater than 3, n is at least 0 and m + n is 11-19. <Formula III>

Wherein B is as defined above, v is greater than 3, r and s are each greater than or equal to zero and v + r + s is 10-18. <Formula IV>

Where B, v, each r and s are as defined above, t is a number greater than or equal to 0, and the sum of v, r, s and t is 10-18. <Formula V>

Where w is from 10 to 24. <Formula VI>

Wherein R ′ is a linear or branched alkyl group substituted with one or more cyclic ether groups, and optionally with one or more hydroxy groups or other ether groups. Dispersing the urethane group-containing prepolymer in the aqueous phase to form dispersed droplets containing the prepolymer, curing the prepolymer to form solid polymer particles dispersed in the aqueous phase, wherein the prepolymer is polyisocyanate and isocyanate-reactive A reaction product of a reactant comprising a substance, wherein the isocyanate-reactive substance comprises at least one high equivalent hydroxymethyl-containing polyester polyol derived from a fatty acid. 5. The hydroxymethyl-containing polyester polyol of claim 4, wherein the hydroxymethyl-containing polyester polyol has an hydroxymethyl group-containing fatty acid having 12 to 26 carbon atoms or an ester of such a hydroxymethylated fatty acid, with an average of at least 2.0 hydroxy, primary amine And / or a reaction product of a polyol, hydroxyamine or polyamine initiator compound having secondary amine groups / molecules. The method of claim 4 or 5, wherein the prepolymer contains an isocyanate group. The method of claim 6, wherein the prepolymer is cured by reaction with a curing agent containing water or amine groups. The method of claim 4 or 5, wherein the prepolymer contains a hydroxy group. The method of claim 8, wherein the prepolymer is cured by reaction with a curing agent containing isocyanate, carboxylic acid, carboxylic acid halide or carboxylic anhydride groups. The method of claim 4 or 5, wherein the prepolymer contains an epoxide group. The method of claim 4 or 5, wherein the prepolymer contains ethylenically unsaturated groups. The method of claim 11, wherein the prepolymer is cured by free radical polymerization of ethylenically unsaturated groups. The method of claim 12, wherein the prepolymer is cured by exposure to UV radiation. The method of claim 4 or 5, wherein the prepolymer contains both isocyanate groups and ethylenically unsaturated groups. The method of claim 14, wherein the prepolymer is cured by reaction with a curing agent having water or amine groups to form solid dispersed polymer particles having ethylenically unsaturated groups. The dispersion according to any one of claims 1 to 3, wherein the polymer particles contain ethylenically unsaturated groups. The dispersion of claim 16 wherein the polymer particles are UV curable. The dispersion according to any one of claims 1 to 3, wherein the polymer particles contain silyl groups. 4. The dispersion according to claim 1, wherein the polymer particles contain carboxylic acid, carboxylic acid salts, sulfonate or quaternary ammonium groups. 4. The dispersion according to claim 1, wherein the polymer particles contain poly (ethylene oxide) blocks. 5. 4. The dispersion according to claim 1, wherein the polymer particles contain one or more groups derived from polyether polyols, polyester polyols or polycarbonate polyols. 5. The compound according to any one of claims 1 to 3, which is composed of surfactants, catalysts, pigments, dyes, fillers, desiccants, rheology and viscosity modifiers, dispersants, surfactants, preservatives, antibacterial agents, pesticides, fertilizers and the like. Dispersion containing at least one additive selected. Adhesive, sealant or coating composition comprising the dispersion according to any one of claims 1 to 3.